I. Field of the Invention
The present invention relates to a system for leak testing industrial components, such as engine blocks.
II. Description of the Prior Art
In the manufacture of industrial products, such as automotive engines, it is oftentimes necessary to subject the various industrial components, such as engine blocks and cylinder heads, to leak testing to ensure that the industrial component will perform properly when assembled into its final configuration. Such leak testing of the industrial component prior to its assembly in the final product avoids incorporating defective industrial components in the final product and the cost associated with such defective products.
There have been previously known leak testing systems used for industrial components, such as engine blocks and cylinder heads (typical), prior to the assembly of the other engine components onto the engine block. These previously known leak testing systems typically comprise a conveyor which conveys the engine blocks to a leak testing unit which performs the required leak test by sealing the passages of the engine block and applying an internal pressure to the now sealed passageways. An engine block which maintains a determined calibrated pressure within its interior for a predetermined period of time, e.g. thirty seconds, would pass the leak test and would then be returned to the conveyor line which conveys the engine block to a subsequent assembly or processing station downstream from the leak testing system.
Conversely, if the engine block does not maintain the desired pressure within the interior of the engine block after a predetermined time period, the engine block is marked as defective and is conveyed by a separate conveyor line from the leak testing system for further processing in an attempt to correct the leakage problem, or for scrappage.
These previously known leak testing systems, however, have suffered a number of disadvantages. One disadvantage of these previously known leak testing systems is that such systems utilize resilient seals which compress against the engine block during the leak test in order to enable pressurization of the internal passages of the engine block. The repeated compression and decompression of the seals against sequential engine blocks, however, cause the seals to rapidly degrade so that the seals must be routinely replaced on a fairly frequent basis, i.e. weekly. Maintenance to the leak testing units to replace the seals, however, requires that the entire conveyor line be shut down during maintenance on the leak testing system. This, in turn, results in stoppage of the entire assembly process for the assembly line.
A still further disadvantage of these previously known leak testing systems is that, in the event that the seals on the leak testing system become worn or damaged, pressure leaks can occur through or around the damaged seal. When this occurs, the leak testing system generates a failure signal indicative that the engine block has failed the leak test when, in fact, the engine block is not defective. However, since the leak testing system has generated a defective engine block signal, the engine block is disadvantageously treated as defective and conveyed by the conveyor system to a defective engine block storage area.
In the prior practice, deterioration or failure of the seals at the leak testing unit was sometimes detected by the occurrence of a number of sequential engine blocks, all of which failed the leak test. In this event, the seals on the leak testing unit were then replaced and the rejected engine blocks retested by the leak testing system. This procedure, however, was both time consuming and labor intensive.
The present invention provides a leak testing system which overcomes all of the above-mentioned disadvantages of the previously known systems.
In brief, the system of the present invention comprises a conveyor system for transporting industrial components, such as engine blocks, to and from a test area having a support surface. A robot is mounted and operable within the test area and this robot includes a manipulator which engages and moves the industrial components.
At least two leak test units, each having means for receiving the industrial component from the robot, are provided wherein each leak test unit includes means for subjecting the industrial component to a leak test after receiving the industrial component from the robot. Each leak test unit generates a failure output signal in response to a failed leak test on the industrial component as well as a pass output signal when the industrial components pass the leak test.
Each leak test unit is movably mounted to the test area support surface so that each leak test unit is movable between an operable position and an inoperable position. In its operable position, the leak test unit is positioned in the test area and is adapted to receive the industrial components from the robot. Conversely, in its inoperable position, the leak test unit is positioned outside of the test area for repair, seal replacement, maintenance and/or the like.
A robot control means controls the movement of the industrial components by the robot between the conveyor system and one or more selected leak test units in response to at least one control factor, such as a failure or pass output signal from one of the leak test units. As will be hereinafter described in greater detail and by way of example only, in the event that an industrial component fails the leak test on one leak test unit, the robot control means then controls the operation of the robot to move the failed industrial component from one leak test unit and to a second leak test unit. A failure of the same industrial component at the second leak test unit would be indicative that the industrial component is, in fact, defective. In this event, the robot control means controls the operation of the robot to move the defective industrial component to the conveyor system to convey the defective industrial component to the appropriate area for reworking, scrappage or the like.
Conversely, a failure of the leak test by the industrial component at one leak test unit followed by a passed leak test at a subsequent leak test unit would be indicative that the first leak test unit requires maintenance, such as seal replacement. In that event, the first leak test unit is moved to its retracted position and thus outside the test area. Simultaneously, the robot control means receives an input signal that the first leak test unit is no longer in operation in the test area. In this event, the robot control means controls the operation of the robot to move the industrial components between the conveyor system and any remaining leak test units that are in their operable position. Consequently, continued operation of the conveyor line may occur without interruption even during maintenance on the individual leak test units, albeit at a reduced capacity.